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Genomes and mutagenesis. Figure 9.15. The Ames test relies on a mutant bacterial strain that is defective in hisG. - Cannot grow on a medium lacking histidine. Identifying Mutagens. - A mutagen-containing disk is placed on an agar plate with the mutant. - PowerPoint PPT Presentation
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Genomes and mutagenesis
Figure 9.15
• The Ames test relies on a mutant bacterial strain that is defective in hisG.
• - Cannot grow on a medium lacking histidine
Identifying Mutagens
- A mutagen-containing disk is placed on an agar plate with the mutant.- Mutagen causes reversion mutations, and colonies start to appear around the disk.
Figure 9.22
• The Ames assay can be modified to test for the mutagenicity of chemicals processed in the liver.
Figure 9.23
• Transposons are complex transposable elements that carry additional genes (e.g., drug resistance).
Mobile Genetic Elements
Figure 9.34
Fig. 11-33
Gene A
Transposon Transposition
Disrupted gene 2
Gene AGene 1 Gene 3
Chromosome
Gene 1 Gene 2 Gene 3
Chromosome